I don't know if this will help in the slightest. Honestly if it even offends you, I'd understand. but here goes:

As terrible, tragic and unfair as this situation is, I think when you consider the "realities" of time travel, you might start to realize that the timeline you got was still the one worth living.

The cruel thing about cause and effect is the ripple each and every action produces. Even the most minute details of our days affect others, which on turn affect others themselves, and the events of the day arise from the macrocosm of everyone doing things all the time.

So, suppose you travel back in time. In just a few short days, if not even less time than that, your attempt to replicate your current timeline would likely result in vast differences in the world, and your future. You can try your hardest, but you're still quickly undoing the reality you once know.

The friendships that you end up forming will likely be with different people, and even the ones with the same people will have different qualities and character. You may not end up getting the same jobs. You might find yourself in different cities, states, countries, even continents.

Which brings us to your wife. (And please bear with me if you can here, because I say all of this as a sincere attempt to help in some small way.)

Look. I'm a romantic at heart. So I'd love to believe that the two of you were simply meant to be together, and it wouldn't matter when you met her, or what was happening. That would be wonderful!

It's just that, relationships and their catalysts are so complicated, you know? They usually form because of a billion different little coincidences. You guys were in the right place at the right time; both of you were ready for each other; and, most of all, life paved a way to allow it to continue.

Who your wife was five years before you met her, tragically, might change the parameters. Who you were five years beforehand might as well. And even if you were both truly star-crossed, well, in this new reality it simply might not have worked because of things out of your control. It could be that the "prime timeline" was the one in which, believe it or not, your time together was both maximized, and guaranteed in the first place, you know?

Now, I am beyond certain that, if you were plopped back in time anyway, that you would try, and fight with your life to do everything you could. Believe me, I would too. I would not rest until I had run out of ideas.

But maybe the fact that you can't is okay. Not "okay" as in, you're fine now or will be fine any time soon. But okay as in, what you had with her at least happened, and it happened for a while.